Weeds cause tremendous global economic losses by reducing crop yields and lowering crop quality. In the United States alone, agronomic crops must compete with hundreds of weed species.
In spite of the commercial herbicides available today, damage to crops caused by weeds still occurs. Accordingly, there is ongoing research to create new and more effective herbicides.
Certain benzisoxazole and benzisothiazole compounds are known to have herbicidal or auxin-like activity (U.S. Pat. No. 3,657,263; EP 442655-A2; E. Chrystal, T. Cromartie, R. Ellis and M. Battersby, Proceedings of the Brighton Crop Protection Conference--Weeds, 1, pp. 189-194 (1993); K. Sato, T. Honma and S. Sugai, Journal of Agricultural and Biological Chemistry, 49, pp. 3563-3567 (1985); and M. Giannella, F. Gualtieri and C. Melchiorre, Phytochemistry, 10, pp. 539-544 (1971)). However, none of those publications describe the herbicidal agents of the present invention.
U.S. Pat. No. 4,844,728 describes certain pyrazole-1,2-benzisothiazole and -benzisoxazole compounds which are used as intermediates in the preparation of pyrazolesulfonamide herbicidal agents. However, the compounds of the present invention are not specifically described in that patent and no herbicidal activity is disclosed for those intermediate compounds.
It is therefore an object of the present invention to provide compounds which are highly effective for controlling undesirable plant species.
It is also an object of the present invention to provide methods for controlling undesirable plant species.
These and other objects of the present invention will become more apparent from the detailed description thereof set forth below.